Regulating means and circuits



Nov. 1, 1927. 1,647,383 H. w. ULRICH REGULATING MEANS AND CIRCUITS 3Sheets-Sheet i Filed Dec. 24. 1920 T Y il by MM/w Nov. 1, 1927.1,647,383

H. W. ULRICHv REGULATING MEANS AND CIRCUITS Filed Deo- 24 1920 5Sheebs--Sheei'I 2 M111 I E f7?. 2f 1 Y{Shasta-sheet :s

Nov. l, 1927.

H. w. ULRICH REGULATING MEANS AN CIRCUITS Filed Deo. '24 19'20 PatentedNov. 1, 1927. Vi

UNITED STATESl PATENT OFFICE.

HORACE W.j ULRICH, OF EAST ORANGE, NEW JERSEY, ASSIGNOR TO WESTERN ELEC-TRIC COMPANY, INCORPORATED, OF NEW YORK, N. Y., A CORPORATION OF NEWYORK.

REGULATING MEANS AND CIRCUITS.

Application led December 24, 1920. Serial No. 433,024.

This invention relates to regulating means and circuits and moreparticularly it relatesv to means for regulating vthe transmissionequivalent of a signalling circuit.

The principal object of this invention is to Lprovide suitable means forregulating the transmission equivalent of a signalling circuitregardless of variations in the conditions aecting the electricalcharacteristics of the circuit. Other and further objects will beapparent from the description of the invention hereinafter given.

In general the transmissin equivalent of a circuit varies due to anumber of dilerent causes. Among these causes may be en umeratedvariations' in the resistance, inductance or capacity of the signallingline or cable, the impedance of the loading coils, va-

riations inthe potentials of the repeater cir cuit batteries, etc.'

The present invention contemplates eliminating the effect of thesevariations by varying some adjustable element of the transmissioncircuit`in such'a manner as to compensate for the -undeslred varlatlons.In the caseof a'four-wire, repeater circuit effects due to all possiblevariations in the two sides of the four-wire circuit may be comensatedfor by varying the like elements f1n the two sides ofthe circuit on theascauses of variation in either side.

This invention will be hereinafter described in detail in connectionwith fourwire repeater circuits in which a single regulating vsystem isemployed Simultaneously to maintain constant the transmission equiyalentof a plurality of four-wire repeater circuits on the assumption that thefour-wire circuits are similarly affected by themeans producing theundesired'variations. Such an assumption would be true, for example,

if compensation were desired for changes in the impedance in thefour-wire signalling lines due to changes in temperature.

'In A. B. Clark Patent 1,438,219,1Decem'- ber 12,' 1922,. an arrangementisdescribed and claimed in which the regulation .of a four-wire circuitis obtained `by* associating a pilot circuit with therepeater circuitsvto 'be regulated -Tle pilot circuit', is employed -the oppositedirection.f

as an arm of a normally balanced Wheatstone bridge and selector switchesresponysive to an unbalanced condition 'of 'the compensating bridgeserve to produce l.changes both in the Wheatstone bridge and 1n thefour-wire circuits to be regulated.

This invention constitutes an improvement of the system of the Clarkpatent mentioned above in that a galvanometer of special constructionyis made responsive to an unbalanced condition of the Wheatstone bridgeto operate a clutch for rotating the switch arm to effectively cut`impedance elements in or out of circuit in such a way as to give theregulation desired. A second feature of this invention comprisesemploying a special automatic arrangement forinsuring the stopping ofthe regulating System whenever personal supervision is required, whilepermitting its continuous operation during normal variations in theresistance of the pilot wire. Still another'feature relates toemploying'a plurality of pilot wires connected in parallel relation asan arm of theWheatstone bridge, whereby a considerable decrease isobtained in the amount'of resistance variation which must be handled,for example, by the regulating system for a given' range of temperaturevariation.

This invention will be better understood by reference to the followingdetailed description taken in connection with the accompanying drawings,in which Figures 1 and 2 when placed side by side represent thepreferred embodiment of this invention adapted to regulate thetransmission equivalent of a four-wire repeater circuit and Figure 3represents the construct-ion in pers ctive of thev alvanometer by meansof w ich the regulatlon is obtained. 4 E,

Referring to Figures 1 and '2 incoming line section 10 and 'outgoingline section 11g represent one side of a four-wirerepeate circuit fortransmitting signals in one direction while the line sections 12 and. 13may be used as the other side. of the four-wirev repeatercircuit fortransmitting si nals in line sections 10 and 11 are two vacuum tuberepeaters 14 and, 1 5 for producing the desired amount of.vamplification o f thesignals in that'fpart of the four-wire circuitinclud- Included etween.

ing linesections 10 and 11.. Similar vacv y uum tube repeaters and 17are connected No. 1,561,892, issued November 17, 1925, to

D. F. l/Vhiting.

Included between the output terminals of repeater 14 and the inputterminals of repeater 15 is a gain adjusting potentiometer 18 which hasa plurality of taps, any one of' which may be connected to the controlelectrode 19 of Vacuum tube repeater 15. The amount of amplification inthat side of the four-wire circuit including the line sections 10 and 11will, therefore, depend upon what tap of potentiometer 18 is connectedat any particular time with the control electrode 19 of tube 15. Thepoint of connection of control electode 19 to the potentiometer 18 isunder the control of the plurality, of relays 20, 21, 22 and 23, onlyone of which is energized at a time. The energization of relays 20 to 23is determined by the position of switch arm 25, the position of which,by mechanism hereinafter described, is determined by the unbalancedcondition of a Wheatstone bridge arrangement. The Wheatstone bridgecomprises two arms 26 and 27 of fixed resistance, a third arm comprisingresistance 28 and that portion of the potentiometer wireI 29 includedbetween point`30 and contact 31 and a fourth arm which comprises thatportion of potentiometer wire 29 included between contact 31.

Iwhich lare connected in vparallel relation through switching ke s 35and 36.

It isto be assume that pilot wire 33 is closely associated with the linesections 10 and 13 in such a way that variations in resistance of linesections 10 or 13 due to tem perature variations'will be accompanied bya corresponding change in the resistance of pilot wire 33. Similarlpilot wire 34 should be associated witg line sections 11 and 12 in sucha Way that temperature variations produce corresponding eifects in linesections 11 and 12 and pilot wire 34. rlhese two pilot wires may, forexample, each com-v prise a twisted pair of the cable, the other pairsof which are employed for transmis sion of signals, in which case thepilot wire, of course, would be adected similarly with the other pairs.0

-Briey the. operation of the regulating system therefore consists in thetemperature variation producinga change fin, the pilot wireresistancefwhich upsets the VVheatstone bridge and, by an arrangementhereinafter described, the unbalanced condition of the l-Vheatstonebridge rotates switch arm 25 to cause the energization of one of therelays 20 to 23 inclusive, thereby changing the connection of controlelectrode 19v to such a point on the potentiometer 18 that thetransmission equivalent of the repeater circuit is made to be of thesame value as it'had previous to thetemperature variation which producedthe unbalanced condition of the lVheatstone bridge.

Before explaining in detail the operation of this invention it willbenecessary to describe the structure and operation of the galvanometerand associated apparatus by means of which the unbalanced condition ofthe Wheatstone bridge produces the regulation desired.

Referring to Fig. 3, the galvanometer system 40 has a pointer 41attached thereto, which, when the VVheatstone bridge is balanced, liesdirectly under the space between the ends of the two right angle levers42 and 43 which are pivoted respectively at points 44 and 45. From thisposition of rest the galvanometer pointer may deflect, under theinfluence of a current passing through the galvanometer coil, until thepointer lies in any position between the stops 46 and 47 on the rockerarm 48. Rocker arm 48 is lpivoted at points 49 and 50.

Ell)

ever, as the rocker arm is raised, the galvanometer is unbalanced andits pointer lies under one of the right angle levers 42 or 43, thepointer 41, as it is raised, carries up with it, the horizontal arm ofone of these right angle levers. The upward "movement thereby given tothehorizontal arm of one of the right angle levers, 43 for example,causes the vertical arm of lever 43 to press against the pin 55 mountedon an extension of the normally Ahorizontal arm 56 whereby the arm 56 isdisplaced from its horizontal position. 1

The effect of displacing horizontal arm 56 will be better understood bynoting that the arm is supported by member 57 which is pivoted at thepoint 58, the horizontal arm 56 being pivotedto the lower end of themember 57. Horizontal arm 56 is, at times, kept in frictional engagementwith a disk 60 mounted on a shaft 61, by means of a coiled spring 62,one end of which is attached to some rigid support (not shown), and theother end of which is fastened to an extension of member 57. Thefrictional enlll) gagement between arm 56 and disk 60 is periodicallybroken by means of a ca m 64 on shaft 52 which operates to produce thedisengagement a't-the same time or a little before the upward movementof rocker arm 48 is produced by cam 51.

When, therefore, the galvanometer pointer is underneath the end of lever43 and the upward movement against rocker arm 48 causes the lower end ofright angle lever 43 to displace the normally horizontal arm 56, the arm56 is not in engagement with disk 60 so that the tiltingl of the arm 56does not affect disk 60. As soon as rocker arm 48 returns to itsoriginal position, cam 64 allows the normally horizontal arm 56 toengage disk 60. Immediately thereafter,

l .with arm 56 at this time, disk 60 is also rotated about equal to thedistance. arm 56 was originally displaced by lever arm 43.

Mounted on the same shaft as disk 60, are a disk 70 (preferably ofinsulating material) and a contact arm 25. Included in a j groove on theperiphery of disk 70 is the potentiometer wire 29 to which Areferencehas already been made in the discussion of u Fig. 2. Contact arm isadapted to make Contact with any one of a plurality of contact studs 71,72, 73, etc. which are set in a stationary b 'ock 75 of rial. Thesecontact studs 71,'etc., each lead to one of the relays controlling theadjustment of the gain adjusting potentiometer.

It is to be noted that the amount shaft 61 yis rotated to vary theposition of contact arm 56 will be tilted. This action therefore,insuresthat the corrective action roduced by the galvanometer system wi beproportional to the change in the resistance of the pilot wire. f

Itis also to be notedthat forv positions of maximum deflection,galvanometer pointer 41 instead of cooperating with the right anglelevers 42 and 43, engages in itsl upward movement with either one of thesup. plementary levers 77 and 78. The reason,

pointer41 for a large deiiection does not:

engage levers'42 or 43 is because levers 42 and ,-43 are hollowed out,near the points about which they are. pivoted, to such an extentthat-,when rocker arm 48 is raised to its highest'positionpointerv 41 isstill out of insulating matement requires personal supervision. The

adjustment of the galvanometer system is such that a deflection of thegalvanometer pointer under one of the supplementary levers 77v or 78,indicates an abnormal condition in either the repeater circuitor thepilot wire system, as would be occasioned, for example, by theshort-circuiting of apart or all of one of 4the pilot wires.

The `continuously operating shaft 52 on which are mounted the cams forlifting the rocker arm 48, disengaging arrn 56 from disk 60, and forrestoring arm 56 to its normally horizontal position, may be driven byany suitable means. Herein it is shown connected by suitable gearing and86 to a. motor 87. If desired, the frictional contact between arm 56 anddisk 60 may be obtained by means of two cork blocks 88 and 89which'arefastened to opposite ends of larm 56.

In .order to put`the regulating system in operation, thel two pilotwires 33 and34 by means of leads 90 and 91, should bc connected into theWheatstone bridge by means of switching keys 35 and 36. The throwingover to operative condition of switching keys 35 and 36 energizes therelay B vby the following circuit-z from grounded battery, winding ofrelay B, conductor v91', contacts 92 of switch 36, and contacts 93 ofswitch 35 to ground. The operation of relay B.

closes the energizing circuit for the lVheatstone bridge by thefollowing path: from point 94, conductor 95, battery 96, resistance lamp97, movable contact 98 of relay B,

amovable contact 99 of the normally deenergized relay D' to thel springcontact 31 of the potent-iometer wire 29. The closing of thislast'circuit therefore connects battery 96 between the midpoint of theWheatstone bridge arms 26 and 27 and the mid-point of arm 28 and thefourth arm which comprises 'pilot wires 33` and 34.Iv

The operation of 'relay B also closes an energizing circuit for relay Eover the followin pathrfromo -grounded battery, windingo relay E,conductor 100, movable contact 101 of the normally deenergized relay D,conductor 102, movable contact 103 of izo' relay B, conductor 104, andmovable contact 105 of normally deenergized relay A, to ground. Theenergization of relay E causes its movablev contact 106 to close-the.switch arm 25 closes an energizing circuit for relay 21 by means of thefollowing path: from grounded battery, winding of relay 21, conductor110, conductor 111, contact 108, and switch arm 25 to ground. Relay 21being energized pulls up its movable contacts and establishes thefollowing connection: from control electrode 19, conductors 112 and 123,movable contact 114 of relay 21, and conductor 115 to point 116 on thegain adjusting potentiometer 18. Control electrode 19 by theenergization of relay 21 is therefore connected to the approximatemidpoint of the potentiometer 18. This is the position desired `for theaverage resistance of the pilot wires 33 and 34 since it allows theconnections to the potentiometer 18 to be varied to give as muchincrease in the transmission equivalent of the circuit as it can bevaried to decrease the transmission ,equivalent of the circuit. l

tion which produces similar effects in the impedance-of the pilot wires33 and 34, such as an increase in temperature, for example. Thisincrease in temperature would increase the resistance of line sections10 and 11 thereby tending to decreafe the transmission equivalent of therepeater circuit. -Pilot wires 33 and 34, however, are similarlyaffected, and the increase in their resistance upsets the balance of theWheatstone bridge, whereby they galvanometer suspension 40 is defiected.

1f, as assumed above, the change in the resistance amounts to anincrease, the galvanometer pointer 41 will be defiected under thehorizontal part of the pivoted arm ,42, and the upward movement ofrocker 'arm 48 will cause pivoted arm 42 to press against the pin120whereby the normally horizontal arm 56 is turned in a clockwisedirection an amount proportional to the deection ofA the pointer 41.Subsequently, the large cams 66 and 67 will restore arm 56 to itshorizontal position 4thereby rotating switch arm 25 over to thestationary contact 73, for exarm 25, contact 73, conductors 121 and 122,

and winding relay 22 to battery and ground. Relay 22 on operating closesthe following connection between potentiometer 18 and Acontrol electrode19: control electrode 19,

amount of potentiometer 18 included in the.

input circuit of tube 15 serves to increase the amount of amplificationin line sections 10 and 11 thereby tending to compensate for thedecrease in amplification produced by the assumed increase intemperature.

At the time switch arm 25 was moved to contact 73, the disk carryingpotentiometer wire 29 was moved in a counter clockwise direction therebyincreasing the amount of the potentiometer wire 29 included inthel/Vheatstone bridge arm containing the pilot wires and at the same timeincreasing the amount of the wire 29 included in that arm of the bridgecontaining resistance 28. Thev regulating apparatus should be, soadjusted that if the increase in the .amount of potentiometer. 18included in the input circuit of tube 15 is suflicient to completelycompensate for the temperature increase, the change in' the relativeproportions of the wire 29'ineluded in the pilot wirev arm 'and arm 28should be such as to restore the balance of the Wheatstonebridge.

lf the changes in the connections for po. tentiometer 18 are sufficientto compensate for the temperature increase, the Wheatstone bridge will,therefore, be balanced again and pointer 41 will return to its positionof rest. No further rotation of the shaft 61 will, therefore be produceduntil the Wheatstone bridge becomes unbalanced again.

lf, however, the change in the connections for potentiometer 18 did notcompensate entirely for the increase in temperature, galvanometerpointer 41 will remain deflected under the horizontal part of thepivoted arm 42 and rocker arm 48 will again cause the pivoted arm 42 topress against pin 120 and tilt arm-` 56'in an amount proportional to theam-ount of deflection of pointer 41. The restoration of. arm 56 tohorizontal position, will cause switch arm '25`t0 be' rotated farther ina counter clockwise direction and it may be assumed, for example, thatit is moved until it vrests on contact 72. The breaking of contactbetween switch arm 25 and contact 73 .leenergizes relay 22. Switch arm25 contacting with stationary contact 72 closes the energizin circuitfor relay 23 which may be trace as follows: from battery, ground,winding of relay 23, conductors 127 and 128, contact 72, and switch arm25 to ground. The energization of relay 23 by connections similartothose previously traced serves to connect the control electrode 19 tothe point 130 of potentiometer 18. It this change in the connections ofpotentiometer 18 is sulicient to compensate for the change in resistanceof the four-wire repeater circuit, galvanometer pointer 41 will moveback to its normal posit-ion of rest. If this last change in theconnections of potentiometer 18 is not suiiicient to compensate for thechange in resistance, still other relays 15, similar to relays 22 and 23may be energized t0 connect still a greater portion of potentiometer 18in the input circuit of tube 15.

It is to be understood, of course, that any number of relays, such as to23, may be 2() employed. In one particular case it was found convenientto employ twenty-one relays, each of which controlled connections to a.diiierent point on the gain adjusting potentiometer.

If, on the contrary, a decrease in temperatureshould take placetherebydecreasing the resistance of the pilot wires and the fourwire repeatercircuit, the unbalance of the VVh'eatstone bridge would be in such adirection as to cause pointer 41 to be deflected under the pivoted arm43 whereby switch arm 25 would be rotated ina clockwise direction. Itwill be readily understood fromcircuits previously traced, that therotation of switch arm 25 in a clockwise direction whereby contact ismade with one of the stationary contacts 132, 133, etc., that relayswill be energized which will serve to decrease the amount ofpotentiometer 18 included in the input circuit of tube 15 therebydecreasing the ampliiication in line sections 10 and 11 and compensatingfor the decrease in resistance.

From the above description it will be apparent that the circuitarrangements described serve to maintain constant, the transmissionequivalent of line sections 10 and 11.

The other half of the four-Wire repeater circuit may be simultaneouslyregulated by the same series of relays, 2O to 23 inclusive.

The gain adjusting potentiometer 134 included between tubes 16 and 17 issimilar t-o potentiometer 18 and has a. plurality of points connected byleads through the lefthand contacts Of.- the relays to the controlelectrode of tube 17. It is apparent from the drawing that whenever, asabove described, the amount of-potentiometer 18 included in the inputcircuit of tube 15 was changed to compensate for changes in resistance,similar changes mere made in potenti-' ometer 134 whereby compensationcan be obtained for the change in resistance of line sections 12 and 13.

It is also'to be understood that the Wheatstone bridge of 2 may beemployed to -and 11 or 12 and 13.

regulate simultaneously, a plurality of fourwire repeater circuitssimilar to the one comprising line sections 10 to 13 inclusive. Theleads 135, 111, 121 and 128 may also be connected respectivelyftoconductors 136, 137, 138 and 139 which lead to the windings of relayssimilar to relays 2O to 23 inclusive which are represented by the block140. The

relays of block 140 may be employed to control the connections for gainadjusting po.- tentiometers located in line sections 141, 142, 143, and144. Blocks 145 and 146 may represent repeater apparat-us similar to theapparatus shown between the line sections 10 If at any time in theoperation of the regulating arrangement, an abnormal change in theresistance of the four-Wire repeater circuits should take place, or ifone of the pilot wires should inadvertently be shortcircuited, forexample, whereby a large deflection of pointer 41 would be obtained, thepointer 41 would be deflected under one of the supplementary members 77or 78. If,

for example, the pointer were deflected underneath the lever 77, rockerarm 48 would cause contact to be made between contacts 79 and 80. Theclosing of this contact as shown in Fig. 2 serves to vlight a lamp 150and energize relay F by the followin circuit: from grounded battery,winding o relay F, conductor 151, lamp 150, and contacts 79 and 80 toground. The energization of relayF may be employed for operating abuzzer 152 which will serve to call to the attention of the personsupervising the apparatus that personal supervision is required. Thelightring of lamp 150 will indicate to the supervisor the source of thetrouble. The deflection of galvanometer pointer 41 underneath lever 78,will light' a signal lamp 153 and will also energize relay F to operatethe buzzer.

Included in the arm 28 and the pilot wire arm of the Wneatstone bridge,are the two windings of the differential relay C. These two windingsoppose each other in their action on the movable contact of relay C, andfor a condition of balance in the Wheatstone bridge or a normalvariation from the balanced condition, the windings are so adjusted thatthe movable contact of relay C is not pulled over to the stationarycontact. If, however. an abnormal degree of unbalance of the Wheatstonebridge takes v place whereby the currents in arm 28` and the pilot wirearm of the bridge have quite dierent values, the contacts of relay Cwill be closed thereby energizing relay .A over the yfollowing circuitifrom grounded battery, winding of relay A, conductor 156, and contactsof relay C to ground.

The energiz'ation of relay L serves to short-circuit the galvanometersuspension 40 by closing a shunt path of low resistance around theterminals of `the high resistance 157 which normally shunts thegalvanometer 40. 'Ihe short-circuiting of galvanometer 40, of course,prevents-injury to the galvanometer 40 from the unusual currents whichwill otherwise flow therethrough reaks The energization of relay A alsothe energizing circuit for relay E which has been previously traced aspassing through movable contact 105 of relay A. The bearking of theenergizing circuit for relay E serves to stop the motor 87 and thepulling over of movable contact 165 lights a lamp 160 and enei/gizesrelay F to operate ,buzzer 152.

Whenever, 1n the operation of the regui, tion. IAs shown in Fig. 2, thetwo end stationary contacts 160 and 161 are not connected to relayswhich control the connections for the gain adjusting potentiometers butare connected to windings of a double relay D. VVheneVer in theoperation of the circuits, switch arm 25 is rotated far enough in eitherdirection to come in contact with either contact 160 or 161, relay Dwill be energized from ground, battery, either conductor 162 or 163, awinding of relay D to either contact 160 or 161, and switch arm 25 toground. The energization of either winding of relay D will serve to pullover Contact 101 thereby breaking the energizing circuit for relay E andstopping motor 87. The energization of relay D will also pull overmovable contact 99 thereby disconnecting thesource of current 96 fromthe Wheatstone bridge. The regulator will, therefore, be inoperativeuntil the necessary manual adjustments-have been made by the attendanttorestore switch arm 25 to some contact located between contacts 160 and161. As soonas switch arm 25 is thus moved, relay D will be deenergized,motor 87 started again, and the source of current 96 connected again tothexWheatstone bridge.

If the two pilot wires 33 and 34 do not happen to have the sameresistance, the pilot Wheatstone bridge, the adjustable resistance F167may be adjusted tobring the pilot wires, lfor example, up to the desiredresistance.

In one case, forexample, arms 26 and 27 of rthe l/Vheatstone bridge eachkhad a resistance of 300 ohms, while the resistance 28 was 9350 ohms,the winding of relay C in circuit with resistance 28 was 200 ohms andhalf of the resistance of wire 29 was 225 ohms. With such values, themaximum resistance of the pilot wires in parallel can be about 9800 ohmsfor efficient operation. The maximum resistance of the pilot wire whichmay be handled eiiciently, is limited by the fact that it has not beenfound feasible to make potentiometer wire 29 have a greater resistancethan about 450 ohms. An appreciable increase of the resistance of wire29 by employing a smaller wire, for eX- ample, causes trouble inobtaining a good Contact between the spring contact 31 and thepotentiometer wire. It has, therefore, bren found preferable instead ofemlploying a single pilot wire to divide the pi ot wire in two andconnect the parts in parallel thereby halving the effective resistanceof the pilot wire arm of the bridge. In the case where the pilot wireresistance arm was of the order of 9800 ohms, and the pilot wire wasdivided and the parts connected in parallel, each part consisted of atwisted pair of No. 19 gauge cable, 125 miles long.

What is claimed is:

1. In combination, a signaling system comprising two line sections, arepeater therebetween, a pilot wire associated with each of said linesections, said pilot wires being connected in parallel and meansresponsive to a change in an electrical condition of said pilotl wiresfor regulating the transmission equivalent of said system. V

2. In combination, a signaling system comprising two line sections, arepeater therebetween, a pilot wire individual to each section, anormally balanced Wheatstone bridge, one arm of said bridge comprisingsaid pilot wires connected in parallel, and means responsive to anunbalance of said bridge for regulating the transmission equivalent ofsaid system.

3. In combination, a signaling system comprising two line sections, arepeater therebetween, an adjustable impedance .element so connected insaid system that the transmission equivalent 0f said system may becontrolled. by said adjustment, a pilot wire associated with each ofsaid line sections, said 'pilot wires being connected in parallel, and

means responsive to changes in an electrical condition of said pilotwires to vary the adjustment of said element.

l4. In combination, a deflecting member, a source of power, atranslating device, a pivoted member the movement of which by saidsource of power is controlled by said deecting member when itsdeflection is of the adjustment of a condition of said device,

a second translating device, and a second pivoted member the movement ofwhich by said so'urce'of power is controlled by said deflecting memberwhen its deflection is greater in vmagnitude than the first men-.

tioned deflection, the movement of said second pivoted member forcontrolling the adjustment of a condition of said second device.

5. In combination, a deflecting member, a source of power, a translatingdevice, a movable member the movement of which by said source of poweris controlled by said deflecting member when its deflection reaches acertain magnitude, the movement of .said movable member controlling theadjustment .of a condition of said device, said movable member beingunresponsive to a defiection of a certain greater magnitude, a secondtranslating device, and a second movable member the movement of which bysaid source of power is controlled by said defiecting member when its.defiection reaches the value to which said first movable -member isunresponsive, the movement of said second movable member controlling theadjustment of said second device to a certain condition.

6. In combination, a deflecting member, a source of power, a pair ofpivoted members -oppositely disposed with respect to said dcf-lectingmember, the actuation of one of said pivoted members by said source ofpower being controlled by a deflection of a cer- Y tain magnitudein theone direction of said deflecting member, a translating device theadjustment of which to a certain condition is controlled by theactuation of said one'of said pivoted members, said other pivoted memberbeing similarly responsive to a deflection in the opposite directionandof a certain magnitude to produce a different adjustment -in theelectrical condition of said device',V a vsecond translating device, and,a

second pair `,of pivoted members oppositely being responsiv ing memberto which said first pair ufl-pivdisposed with respectl to .sa-iddeflecting' member, the actuation osaid second pair of pivoted membersby said source of Apower d eections of said defiectoted membersv isunrespgnsive .and vconnections whereby the actuation'l of' 'said secondpair of pivoted memberscontrol an electrical condition of Sadsecond'tran'slatng device.

'-7, In' combination,'afdeflecting member, a source of power, sa"plurality 0I stationary contacts, translating devices connect-ed to a'plurality of said stationary contacts, a movable switch arm cooperatingwith sald sta- I tionary contacts for controlling the electricalcondition of said translating devices, and

a pivoted member the movement of which venergized by said source ofpower for causing said deflecting memberl when deflected to contactwithV said pivoted member and cause the movement thereof, said pivotedmember having such a configuration as to contact-with said deflectingmember only when the deflections of said deflecting member are of lessthan a' certain magnitude.

9. In combination,v an electrical circuit, a deflecting memberresponsiveto conditions vaffecting the electrical characteristics of'said circuit, a plurality of stationary contacts, 'a movable switch armcooperating with said contacts, means associated with said stationarycontacts for controlling .an electrical condition of said circuit, lasource of power, a pivoted member Athe movement of which controls theposition of said switch arm, and means energized by said source .ofpower for causing said defiecting member when deflected to contact withsaid pivoted member to cause a movement thereof.

10. In combination, an electrical circuit, a deflecting memberresponsive to conditionsallee-ting electrical characteristics 'of saidcircuit, a plurality of stationary contacts, a

movableA switcharm cooperating withsaid stationary contacts, meansassociated with said stationary/ contacts `for controlling an electricalcondition of said circuit, a source Y.of power, a pair of pivotedmembers oppositely disposed with respect to said deflect-- -ing member,saidv pivoted members being adapted to control the position of saidswitch arm, and means energized bv said source of power for causing saiddefiecting member when deflected to contact'with' one v of said pivotedmembers to cause a movement thereof whereby the position .of said switcharm is controlled. Y 11. In combination, a signaling circuit, means forregulating an electrical condition'of said circuit, said meanscomprisinga` pilot wire associated with said circuit, la ri,

def-lecting `call condition o'fsaid pilot wire, a source of power, apivoted member adapted to vary member responsive to an electri` 'I thetransmission equivalent of said circuit, v

means energized by said source of power to V cause a movement of saidplvoted member f when said deectingmember is de flected'a certainmagnitude, a second pivoted member adapted to be moved by said lastmeans when a greater deliection of said defiecting member occurs, anindicating device and means controlled by the movement ot said secondpivoted member for operating said indicating device.

12. In combination, a normally balanced Wheatstone bridge network, agalvanometer responsive to an unbalanced condition of said bridge, andmeans responsive to an abnormal deflection of said galvanometer forshort-circuiting said galvanometer.

13. In combination, a normally balanced Wheatstone bridge network, adeflecting member responsive to an unbalanced condition of said bridge,a source of power, a pivoted member, means energized by said source andcooperating with said detiecting member for causing a movement of saidpivoted member, and connections controlled by a movement of said pivotedmember i'or shortc'i.rcuiting said deflecting member.

14. In combination, an electrical circuit, a defiecting memberresponsive tovariations aiiecting the electrical 'condition of saidcircuit, a source of power, means for ad-y justing said electricalcircuit, an arm periodically moved by said source and arranged tocooperate with said defiectmg member when it deflects a certain amount.

to control said adjusting means, and means responsive to an abnormaldeflection of said defiectng member for rendering said sourceinedective.

15. In combination, a normally balanced Wheatst'one bridge network, agalvanometer res onsive to an unbalanced condition, of said ridge, asource of currentfor sald bridge, and means responsive to an abnormaldefiection of said galvanometer for disconnecting said source from saidbridge.

16. In combination, a normally balanced VVheatstone bridge network, agalvanom-l eter responsive to an unbalanced condition of said network, asource of current con-y nected between the junctions of opposite arms ofsaid bridge, and means responsive to an abnormal deflection of saidgalvanometer for preventing saidsource from supplying appreciablecurrent to said bridge.

17. In combination, a normally balanced VVheatstone bridgernetwork, adifferential relay having windings in adjacent arms of said network,said relay being normally deenergized, an electrical circuit, moansresponsive to an unbalance of said bridge for varying the electricalcondition of said circuit, andconnections controlled by said rela forrendering said means inoperative wliienever the current in one windingof said relay becomes greater by a certain amount than the current inthe other windino'.

18. In combination, an electric circuit, a plurality of stationarycontacts, a movable yswitch arm cooperating with said contacts,

means controlled by variations in the conditions affecting theelectrical characteristics of said circuit for moving said switch arm,connections from said plurality of stationary contacts for controllingan electrical condition of said circuit, an additional contact on eitherside of said plurality of contacts with reference to the movement ofsaid switch arm, and connections controlled by the association of saidswitch arm with one of said additional contacts for rendering said first`means inoperative. l

20. In comblnation, a line, a potentiometer in shunt to `said line, adeflecting member responsive to change in the conditions affecting theelectrical characteristics of said line, a periodically operating memberadapted to engage said delecting member, a pivoted member actuated bysaid periodically operating member through said delecting member,connections controlled by said pivoted member for controlling saidpotentiometer, and means controlled by; a deflection of said detlectingmember for restoring said deflecting member to its normal position.

21. In combination, a plurality of regulating elements, an electriccircuit including a variable number of said regulating elements, adefiecting member responsive to change in the conditions aEecting theelectrical characteristics of said circuit, a periodically operatingmember adapted .to engage said def'lecting member, a pivoted memberactuated by said periodically operating member through said delectingmember, connections controlled by said pivoted member for effectivelyremoving from said circuit one of said elements and at other times foreffectively removing another of' said elements from said circuit, andmeans controlled by a deflection of said deflecting member for restoringsaid deflecting member to its normal position.

22. In combination, a plurality of regulating elements, an electriccircuit including a variable number of said elements, av deflectingmember responsive to change of conditions afecting the characteristicsof said circuit, a periodically operating member adapted to en age saiddeflecting member,

ivoted mem er actuatedby sald periodii. operatmg member through saiddelli() trolled by said pivoted member, a plurality of stationarycontacts cooperatingwith said switch arm, and connections from saidStationary contacts for controlling the number of said regulatingelements included in said circuit.

23. In a signalling circuit, transmission regulating means thereforcomprising a gal- 'vanomter, a regulating element, and means forcontrolling said element by saidl galvanometer.

24.1In combination a signalling circuit, means for maintainingsubstantially constant transmission ofthe signals in said circuit, saidmeans comprising a galvanometer, a regulating element in said circuit,and means for controlling said element by said galvanometen 25. Incombination, a signalling circuit, transmission regulating meanstherefore comprising a galvanometer, aplurality of regulating elementsin said circuit, and means for controlling said elements byv saidgalvanometer. y

26. In combination,l a signalling circuit, transmission regulating meanstherefor comprising a galvanometer pointer` responsive to change in acondition of said circuit, a periodically operating member adapted toengage said pointer, a pivoted member controlled by said pointer andsaidperiodically operating member, and a regulating element in said circuitcontrolled by said pivoted member.

27. In combination, a signalling circuit, transmission regulating meanstherefor comprising a galvanometer, a pluralit of 'regulating elementsin said circuit, anii. of relays controlled by said galvanometer forcontrolling said elements.

28. A regulating element, a motor `for driving said element, aWheatstone bridge, means responsive to 'a condition of unbalance of saidbridge Within certain limits for determining when said motor shall drivesaid element, and translating means responsive to a condition of greaterunbalance of said bridge. f

In witness whereof, I hereunto subscribe my name this .22nd day ofDecember, A. D.,

HORACE W. ULRICH.

a series

